Enzymes Flashcards
What is activation energy
The energy required to enable a reaction to take place
What’s the active site
The area on an enzyme molecule to which the substrate binds
What’s a buffer
A substance that resists a change in pH when acid or alkali is added
What’s a catalyst
A substance that increases the rate of a reaction but does not take part in the reaction, and so is reusable
What’s a coenzyme
An organic non-protein molecule that binds temporarily with the substrate to an enzyme active site. It is essential for enzyme activity
What’s a cofactor
A molecule or ion that helps an enzyme to work. It may be an inorganic ion or a coenzyme
What’s a competitive inhibitor
A substance that reduces the rate of an enzyme-controlled reaction by binding to the enzyme’s active site
What’s denaturation
An irreversible change in the tertiary structure of a protein molecule. It leads to loss of function in most proteins
What’s end product inhibition
The regulation of metabolic pathways where the last product in a sequence of enzyme-controlled reactions becomes an inhibitor of one of the enzymes earlier in the sequence
What’s an enzyme
Biological catalyst that speeds up metabolic reactions inside cells
What’s the enzyme substrate complex
The intermediate structure formed when a substrate molecule binds to an enzyme active site
What’s a globular protein
Proteins with relatively spherical molecules, soluble in water, often having metabolic roles in organisms
What’s induced fit hypothesis
The theory of enzyme action in which the enzyme molecule changes shape to fit the substrate molecule more closely as it binds to it
What’s inhibition
The slowing of an enzyme-controlled reaction by substance that slows or prevents the formation of enzyme-substrate complexes
What’s the lock and key hypothesis
The theory of enzyme action where the enzyme active site is complementary to the substrate molecule
